Study of the lasso peptide microcin J25 effect on the E. coli

GALVÁN E; CHALÓN MC; MINAHK CJ; BELLOMIO A

San Miguel de Tucumán

Congreso; III Latin American Federation of Biophysical Societies (LAFeBS) ? IX IberoAmerican Congress of Biophysics ? XLV Reunion Anual SAB; 2016

SAB

p { margin-bottom: 0.25cm; line-height: 120%; }a:link { }The antimicrobiallasso peptide microcin J25 (MccJ25) displays a bacteriostaticactivity by inhibiting RNA polymerase. This peptide is secreted byEscherichia coli and it can also target the enzymes of therespiratory chain on the bacterial membrane. E. coli has two typeterminal oxidoreductases, the cytochrome bd (bdI and bdII) andcytochrome bo3. Previously, it was demonstrated that the MccJ25inhibits the cell respiration and increases the superoxideproduction. In this work, the effect of this peptide on E. coli C43cytochrome deficient strains was studied. We evaluated the NADHdehydrogenase activity and the oxygen consumption rate. MccJ25-GA1and Y9F2 are two modified peptides obtained in our laboratory. Theability of these peptides to inhibit the ubiquinol oxidase activityand to produce a superoxide overproduction in the purifiedcytochromes was also analyzed. Our results indicate that both,cytochrome bdI and bo3, are necessary for MccJ25 inhibitory effect.Because of its extreme resistance to proteolytic degradation and hightemperatures, MccJ25 is a potential candidate for a number ofapplications including food preservation and treatment of food-bornediseases. Acknowledgements: We thanks to phD Gennis, R. andSchurig-Briccio L. from Deparment of Biochemistry, University ofIllinois for give us the E. coli C43 strains and cytochromesoverexpressing plasmids. References1 Bellomio, A.,Rintoul, M.R., and Morero, R.D. (2003). Chemical modification ofmicrocin J25 with diethylpyrocarbonate and carbodiimide: evidence foressential histidyl and carboxyl residues. Biochem. Biophys. Res.Commun. 303, 458?4622 Chalon, M.C.,Bellomio, A., Solbiati, J.O., Morero, R.D., Farias, R.N., andVincent, P.A. (2009). Tyrosine 9 is the key amino acid in microcinJ25 superoxide overproduction. FEMS Microbiol. Lett. 300; -96.